Pests and Pest Control

Pests

• Any troublesome, destructive, or annoying organism

• Insects eat about 13% of all crops in North America

• Only 1/8th of insects are pests.

Pests

• Many insects are very beneficial.– keep soil “healthy”– maintain food crops– pollinators

Pesticides

• Chemicals that kill insects, weeds, and other crop pests

• Humans have created very effective pesticides

• Pesticides can harm beneficial plants, insects, wildlife, and even people

Pesticide Resistance

• The ability of pests to survive exposure to a particular pesticide.

– Occurs when large amounts are sprayed continually

– Pest population evolve resistance to the pesticide

Pesticide Resistance

Human Health Concerns

• Pesticides are designed to kill organisms– May also be dangerous to humans

• Cancer rates among children in areas that use large amounts of pesticides are higher than the national average

• Nervous systems disorders may be common• Pesticide factory workers may become ill• Accidental chemical leaks may endanger people in

the area• Safety guidelines must be followed to protect

people

Persistent Pesticides

• A pesticide is persistent if it does not break down easily or quickly in the environment.

– Accumulates in the water and soil– Many remain in the environment for many

years

A Harmful Pesticide

• Chlorinated Hydrocarbons– cheap, easy to use, kills many different

insects, kills long after application, doesn’t wash away by rain, may not be very toxic to humans

– Example: DDT • was banned in the United States in 1972 but is still

found in foods decades later• stored in body fats

Bioaccumulation

• When something, such as a pesticide, becomes more and more concentrated as it moves up the food chain– DDT caused eggshell thinning in eagles and

ospreys

Biological Pest Control

• Use of living organisms to control pests

– Natural Predators– Pathogens– VNT– Natural Chemicals– Growth Regulators

Pathogens

• Organisms that cause disease

– Bacillus thuringiensis is a bacterium that kills caterpillars

VNT

• plant varieties that are resistant to certain fungi, worms, and viruses

Natural Chemicals

• From plants are sold as pesticides

– less harmful to humans and animals and is biodegradable

Example:• chrysanthemums

Growth Regulators

• Chemicals that interfere with the life cycle

– pheromones– sterilize males

Integrated Pest Management (IPM)

• Aims to reduce pest damage

– Uses different management techniques according to the management goal and species involved

– Used at appropriate times in the growing season

Steps of an IPM

• Monitor crops from time of planting

• Identify pests

• Create a program– First try biological methods– Cultivation controls

• Vacuuming pests

– Small amounts of pesticide as a last resort• Change the pesticide overtime to reduce pesticide

resistance

Genetic Engineering

• Using technology in which genetic material in a living cell is modified.

– Take genes from one organism and introduce them into another organism

– Creates genetically modified (GM) plants• Used for pesticide resistance• Increased “life” of produce• Improved taste

Genetic Engineering

Genetic Engineering

• Many foods are genetically engineered

– Many have not been fully tested for environmental impacts

• May cause future problems

Sustainable Agriculture

• Farming that conserves natural resources and helps keep the land productive indefinitely– Minimizes the use of:

• Energy• Water• Pesticides• Fertilizers